Question

two cars A and B race each other. the car A ran for 2 min at a speed of 7.5 km/h , slept for 56 min and again ran for 2 min at a speed of 7.5 km/h .find the average speed of the car A in the race

Answer 1

the average speed of the car A in the race 0.5 km/hr

distance = speed×time

distance 1 = 7.5×2/60
                 = 0.25 km

distance 2 = 7.5×2/60
                 = 0.25 km

Total distance = distance 1+distance 2 = 0.5 km
Total time = 2+2+56 = 60min = 1 hr

Average speed = 0.5 km/hr

Answer 2

The Car A ran at speed of 7.5 km/h for first time for 2 minutes or 1/30 hour.

So, distance covered in first case = speed × Time
= 7.5 × 1/30
= 0.25 km

Car A takes rest for 56 minutes.

Then car A ran at 7.5 km/h again for 2 minutes or, 1/30 hours.

So, distance = speed × Time
= 7.5 × 1/30
= 0.25 km


So, Total distance = (0.25+0.25) km
= 0.50km

Total Time taken = (56+2+2) minutes
= 60 minutes
= 1hr.

Average speed = Total Distance/Total Time
= 0.50/1
= 0.5 km/hr


Answer) The average speed of car A for whole race is 0.5 km/hr.